Road Salt (usually sodium chloride - NaCI) impactssoils, vegetation, wildlife, infrastructure, and even human health each time it is put to use in melting snow around cities. It is, not always, but most of the time, composed of approximately 60% chloride and 40% positive ion. Sodium Chloride melts ice by reducing the freezing point of water; however, the chloride component is toxic to the environment, for it can stunt the growth of organisms and change the composition of algae. Road salt is used to clear the roads of snow and ice to make it safe for vehicles and pedestrians. The salt melts the ice and snow of the roads. The chloride that comes from the road salt is a water pollutant, and that pollutant mixes in with the melted ice and snow. The polluted water goes into the rivers, lakes, wildlife, and groundwater. Road salt is an effective resource for melting ice on frozen winter roads; however, the majority of it travels into the environment after it is used, and it becomes a harmful pollutant. Road salt comes into groundwater as well as surface water, where it threatens the life of many aquatic organisms, and can be harmful to human health when it contaminates drinking water.
Where does road salt come from? (More information and the original site can be found here) According to BBC News, the UK gets its road salt from 3 main mines, which are all about a mile underground. They are all formed from the fact that millions of years ago, Ireland and the UK were covered by inland seas. They washed out caves underground, and resulted in evaporating, leaving ocean salt behind in the underground caverns. The salt is mined with machines known as continuous miners, which have metal blades that cut out the salt. The salt is then put on a conveyor belt to await further treatment. After it is fully treated, it is stored before being shipped to people and companies that want to buy it. ( <--- A big block of road salt from an underground cave.)
Benefits of Road Salt:
Because of the urban lifestyle of modern society and the economy that makes the service of goods and products essential, roadways must be maintained in the winter to ensure safe and dependable driving conditions. Salt is especially useful to prevent snow and ice from bonding to the pavement so that snowplows can clear the road. Also, applying salt dramatically lessens traffic accidents. Within hours of applying road salt after a snow storm, a study from Marquette University found that there was an 85% reduction in traffic crashes and an 88.3% reduction in accidents causing injuries. Spreading road salt assures a higher amount of friction on icy roads, thus providing more safety and improves the driver’s ability to maintain control. In some circumstances, putting road salt on the roads can dramatically cut the cost of maintaining a safe road, because it makes the duties of snow plows easier and less time consuming. Sodium Chloride is also significantly cheaper than most other de-icers, which makes it practical for the government to use. More information on the benefits of road salt can be found at this website here.
(Road Salt Prevents Many Automobile Accidents in the Winter) Animal Life Affected by Road Salt According to this site, in March of 2010 in Cumbria, in the UK, about 75 great crested newt carcasses were found in a railway station car park, and it appeared that they were migrating to their seasonal breeding grounds after hibernation. A fortnight before these newts attempted to get to their breeding pond, road salt had been spread across the car lot due to unusually cold weather in the area. There was enough evidence to see that this road salt's residue had kiled off the 75 great crested newts. The site also mentions; "There are a few anecdotal reports of UK amphibian mortality associated with road salting, and salt treatment of ponds. As in this case, incidents tend to occur when an unusually late period of freezing weather is swiftly followed by much milder temperatures. We would like to raise awareness of the apparent potential for road salt to negatively impact amphibians, and recommend that judicious caution is exercised in the use of road salt near amphibian migration routes, particularly in March and April; road maintenance contractors should be aware of this risk."
Road salt is applied to roads in 26 states in the United States, yet the impacts on aquatic organisms lack sufficient studying. Both the adult and larval amphibians are known to be especially sensitive to changes in their environments. In one study, scientists investigated the possible effects of road salt on two vernal-pond-breeding amphibian species—the spotted salamander and the wood frog. In the Adirondack Mountain Region of New York, road salt travelled up to 172 m from the highways into the wetlands. Studies reveal that the egg mass densities of spotted salamanders and wood frogs were twice as high in forested pools than in roadside pools, where salt contamination is exceptionally high.More information can be found at this site.
When salt leaves the road, it erodes soil and can damage trees and vegetation as far as 650 feet away. Roadsides also can become an artificial salt lick which is attractive to animals such as moose and elk. This causes an increased amount of road kill because of the attraction to the salt near the road.
States of the U.S.A. and their Acts Against Road Salt ContaminationBefore the 1940's, American states relied on plowing for getting rid of snow and ice on the roads. Salt was simply used to prevent road sand from freezing at that time. In 1941-1942, New Hampshire became the first state to put a limit on road salt use. That year 5,000 tons of salt were used on New Hampshire's roads."After World War II, as the expanding highway system became essential to the public and the national economy, road salt use began to soar. The bare-pavement concept, under which motorists could expect snow- and ice-free pavements shortly after storms, soon became a policy in most cities and their suburbs. As a result, salt use doubled every 5 years during the 1950s and 1960s growing from 1 million tons in 1955 to nearly 10 million tons less than 15 years later." (the effect of road salt after winter on the nearby trees.) Road Salt Effects: - Contamination of off road water sources - The erosion and contamination of soils due to soil structure - The osmotic balance and rate of plant growth are altered, and roadside trees and plants are damaged or decreased in population. The flowering of this vegetation, the seed germination, and the roots are also negatively affected by road salt pollution. - The effects of road salt on vegitation destroy wildlife habitats and create problems with salt toxicity in the blood of animals, resulting in population declines. - Infrastructure: road salt increases the corrosivity of snow and water, damaging bridges, roads, cars, etc. through corrosion and rust - Human health: dietary sodium increase from road salts has been associated with hypertension - The amount of Sodium Chloride used each winter--over 20 million tons-- is about thirteen times more salt than what is used by the entire food industry. - The amount of snow and ice road salt melts depends on the temperature: road salt is affective from freezing temperature to around 15 degrees F, so when the temperature is below the fifteen degrees the rad salt isn't actually helping and instead being washed off the roads into water and soil - "It only takes one tablespoon of road salt to permanently pollute five gallons of water"
The U.S. Geological Survey reported that 40% of U.S. streams in and around northern cities have destructive amounts of chloride found from de-icing roads in the winter. Streams found in cities carry 88 tons of chloride per square mile out of watershed land, as opposed to just six tons per square mile in a forest watershed. High measurements of chloride can inhibit plant growth, stunt reproduction and decrease the diversity in organisms in streams. Chloride can contaminate drinking water supplies, especially in wells near highways. Chloride in groundwater was more common in urban areas. Salt in drinking water can pose a concern for people on low sodium diets, becoming a hidden source of sodium. This website contains more information on the effects of road salt.
Research Around Road Salt and Current Events: Road salt can often affect plants and creatures, whether they drink the contaminated water or live in it. In Pickering, Canada, it was discovered by researchers from the University of Toronto that road salt had seeped into streams and groundwater, causing the salt level in that area to be similar to the salt level found in oceans. They also found that the water from this area collected in a lagoon nearby, on the shore of Lake Ontario, and it was poisoning the water. A geology professor from the university of Toronto named Nick Eyles stated that about 3,600 tons of road salt end up in the lagoon every winter and continue to poison it for the rest of the year. (more information about this incident can be found here) Researchers at the University of Minnesota--Twin Cities conducted an experiment to discover the result of road salt after it is used on roads. They calculated the amount of salt being added to the system through road treatments, household use, wastewater dumping, agriculture, and other sources. They also calculated the amount of salt flowing out of salt flowing out of the system, though rivers and streams. They discovered that only about 30% of road salt used in the Twin Cities area is carried out by the Mississippi River, while the remaining 70% seeps into the area's watershed, posing as a contamination threat for residents in the area. Road salt seeps into rivers and lakes--more info The issue of road salt having a negative effect on aquatic ecosystems was first recognized in the early 1960’s. Road salt usage in the United States increased consistently starting in the 1940’s up to this decade. Urban development has also increased rapidly, which causes a rise in the necessity of road salt to melt winter roads. 17 major metropolitan areas around the United States were sampled for chloride in the water quality. Samples were collected by submerging sample bottles in the center of a stream or by using a weighted-bottle sampler to collect cross-section samples from streams. At Wilson Park Creek in Milwaukee, some of the results of the toxicity of road salt were that in chronic C. Dubia, no young were produced when the chloride concentration was 1770 mg/L or greater. Complete mortality was seen as a result of chloride concentrations of 2420 mg/L or greater.More information on this experiment can be found here
(Road Salt Runoff Affects Ecosystems and their Inhabitants)
(Many Wildlife Species are Negatively Affected by Road Salt Runoff)
GOVERNMENTS (state, national) INTERACTIONS WITH ROAD SALTS:
- Citizens of the U.S.A. can use a lot of road salt every winter, ending up to be somewhere around 22 million tons of road salt are used, if not even more than that. - Most common used road salt is sodium chloride, which is effective and inexpensive (NaCi) - In the U.S eight to twelve million tons of NaCi road salt a year are used. - Massachusetts alone alloted $35 million for snow removal instead of the previous years $15 million- if the state reduced salt use it would benifit them financially and environmentally - Example of a government dealing with the problems (which mass. could follow their lead) that come from road salts: Canada setting up plans in advance for the use and amount of road salt
Alternatives: -More high tech application of road salt will reduce amount used, however this is more costly- "The state of Indiana implemented this approach last winter, saving 228,000 tons of salt, and -More than $13 million dollars in salt and overtime costs, according to a state report." -Alternatives to NaCi road salt include calcium magnesium acetate and potassium acetate- this site states that, "Even as road salt began to be implicated for environmental damage in the 1960s and 1970s, its use increased to 10 million tons annually in the U.S. and 3 million in Canada (SI 1983). By the 1990s, a variety of alternative deicers CMA, CG-90, NaFo, Freezgard + PCI, Ice Stop CI, Quiksalt + PCI, and urea—were shown to be effective in studies by the Washington Department of Transportation, the Federal Highway Administration, or the City of Ottawa, Ontario (Nevada Milepost 1993,Better Roads 1989, 1991)."
-By deicing the roads before the storm, less salt is needed -"In addition to environmental benefits, using less salt slows its corrosive effects on bridges and cars." -A Minnesota town is testing a previous pavement surface so that melting snow soaks right through, rather than running off into waterways. -Place heating tubes under the roads to melt the ice without salt -New plow blades prove to be more effective to eliminate layers of snow -Wetting the road salt before placing it on the roads so the salt won't bounce off the road - Properly store road salt on an impervious surface away from rain so that runoff doesn't cause damage in the environment or waste purchased road salt - Deicers are usually utilized at a higher rate than recommended, so training applicators or programming road salt trucks by computer would be helpful to avoid overusing road salt, leaving extra behind after the snow is melted - Wetting the road salt before use speeds the melting process and reduces the scatter of salt particles on the road when applied Another site listing alternatives to road salts **Here is a link of how you can help prevent road salt contamination Some ways on how to prevent harmful effects of road salt are to not overuse salt on roads. Salt is only useful for thawing roads before snow and ice fall. By creating a layer of salty moisture that restricts freezing, it stops snow and ice to bond with pavement. More ways to prevent pollution is found here . http://cseo.mtu.edu/community/publications/wellspring/.htmlsummary of road salt and alternative strategies
Governments can limit the amount of road salt permitted to each state per road/highway
ROAD SALT
By Tara, Elizabeth, Alex G., and SarahTable of Contents
1. Road SaltROAD SALT
Road Salt (usually sodium chloride - NaCI) impactssoils, vegetation, wildlife, infrastructure, and even human health each time it is put to use in melting snow around cities. It is, not always, but most of the time, composed of approximately 60% chloride and 40% positive ion. Sodium Chloride melts ice by reducing the freezing point of water; however, the chloride component is toxic to the environment, for it can stunt the growth of organisms and change the composition of algae. Road salt is used to clear the roads of snow and ice to make it safe for vehicles and pedestrians. The salt melts the ice and snow of the roads. The chloride that comes from the road salt is a water pollutant, and that pollutant mixes in with the melted ice and snow. The polluted water goes into the rivers, lakes, wildlife, and groundwater. Road salt is an effective resource for melting ice on frozen winter roads; however, the majority of it travels into the environment after it is used, and it becomes a harmful pollutant. Road salt comes into groundwater as well as surface water, where it threatens the life of many aquatic organisms, and can be harmful to human health when it contaminates drinking water.
Where does road salt come from?
(More information and the original site can be found here)
According to BBC News, the UK gets its road salt from 3 main mines, which are all about a mile underground. They are all formed from the fact that millions of years ago, Ireland and the UK were covered by inland seas. They washed out caves underground, and resulted in evaporating, leaving ocean salt behind in the underground caverns. The salt is mined with machines known as continuous miners, which have metal blades that cut out the salt. The salt is then put on a conveyor belt to await further treatment. After it is fully treated, it is stored before being shipped to people and companies that want to buy it.
Benefits of Road Salt:
Because of the urban lifestyle of modern society and the economy that makes the service of goods and products essential, roadways must be maintained in the winter to ensure safe and dependable driving conditions. Salt is especially useful to prevent snow and ice from bonding to the pavement so that snowplows can clear the road. Also, applying salt dramatically lessens traffic accidents. Within hours of applying road salt after a snow storm, a study from Marquette University found that there was an 85% reduction in traffic crashes and an 88.3% reduction in accidents causing injuries. Spreading road salt assures a higher amount of friction on icy roads, thus providing more safety and improves the driver’s ability to maintain control. In some circumstances, putting road salt on the roads can dramatically cut the cost of maintaining a safe road, because it makes the duties of snow plows easier and less time consuming. Sodium Chloride is also significantly cheaper than most other de-icers, which makes it practical for the government to use. More information on the benefits of road salt can be found at this website here.
Animal Life Affected by Road Salt
According to this site, in March of 2010 in Cumbria, in the UK, about 75 great crested newt carcasses were found in a railway station car park, and it appeared that they were migrating to their seasonal breeding grounds after hibernation. A fortnight before these newts attempted to get to their breeding pond, road salt had been spread across the car lot due to unusually cold weather in the area. There was enough evidence to see that this road salt's residue had kiled off the 75 great crested newts. The site also mentions;
"There are a few anecdotal reports of UK amphibian mortality associated with road salting, and salt treatment of ponds. As in this case, incidents tend to occur when an unusually late period of freezing weather is swiftly followed by much milder temperatures. We would like to raise awareness of the apparent potential for road salt to negatively impact amphibians, and recommend that judicious caution is exercised in the use of road salt near amphibian migration routes, particularly in March and April; road maintenance contractors should be aware of this risk."
Road salt is applied to roads in 26 states in the United States, yet the impacts on aquatic organisms lack sufficient studying. Both the adult and larval amphibians are known to be especially sensitive to changes in their environments. In one study, scientists investigated the possible effects of road salt on two vernal-pond-breeding amphibian species—the spotted salamander and the wood frog. In the Adirondack Mountain Region of New York, road salt travelled up to 172 m from the highways into the wetlands. Studies reveal that the egg mass densities of spotted salamanders and wood frogs were twice as high in forested pools than in roadside pools, where salt contamination is exceptionally high.More information can be found at this site.
When salt leaves the road, it erodes soil and can damage trees and vegetation as far as 650 feet away. Roadsides also can become an artificial salt lick which is attractive to animals such as moose and elk. This causes an increased amount of road kill because of the attraction to the salt near the road.
States of the U.S.A. and their Acts Against Road Salt ContaminationBefore the 1940's, American states relied on plowing for getting rid of snow and ice on the roads. Salt was simply used to prevent road sand from freezing at that time. In 1941-1942, New Hampshire became the first state to put a limit on road salt use. That year 5,000 tons of salt were used on New Hampshire's roads."After World War II, as the expanding highway system became essential to the public and the national economy, road salt use began to soar. The bare-pavement concept, under which motorists could expect snow- and ice-free pavements shortly after storms, soon became a policy in most cities and their suburbs. As a result, salt use doubled every 5 years during the 1950s and 1960s growing from 1 million tons in 1955 to nearly 10 million tons less than 15 years later."
(the effect of road salt after winter on the nearby trees.)
Road Salt Effects:
- Contamination of off road water sources
- The erosion and contamination of soils due to soil structure
- The osmotic balance and rate of plant growth are altered, and roadside trees and plants are damaged or decreased in population. The flowering of this vegetation, the seed germination, and the roots are also negatively affected by road salt pollution.
- The effects of road salt on vegitation destroy wildlife habitats and create problems with salt toxicity in the blood of animals, resulting in population declines.
- Infrastructure: road salt increases the corrosivity of snow and water, damaging bridges, roads, cars, etc. through corrosion and rust
- Human health: dietary sodium increase from road salts has been associated with hypertension
- The amount of Sodium Chloride used each winter--over 20 million tons-- is about thirteen times more salt than what is used by the entire food industry.
- The amount of snow and ice road salt melts depends on the temperature: road salt is affective from freezing temperature to around 15 degrees F, so when the temperature is below the fifteen degrees the rad salt isn't actually helping and instead being washed off the roads into water and soil
- "It only takes one tablespoon of road salt to permanently pollute five gallons of water"
The U.S. Geological Survey reported that 40% of U.S. streams in and around northern cities have destructive amounts of chloride found from de-icing roads in the winter. Streams found in cities carry 88 tons of chloride per square mile out of watershed land, as opposed to just six tons per square mile in a forest watershed. High measurements of chloride can inhibit plant growth, stunt reproduction and decrease the diversity in organisms in streams. Chloride can contaminate drinking water supplies, especially in wells near highways. Chloride in groundwater was more common in urban areas. Salt in drinking water can pose a concern for people on low sodium diets, becoming a hidden source of sodium. This website contains more information on the effects of road salt.
Research Around Road Salt and Current Events:
Road salt can often affect plants and creatures, whether they drink the contaminated water or live in it.
In Pickering, Canada, it was discovered by researchers from the University of Toronto that road salt had seeped into streams and groundwater, causing the salt level in that area to be similar to the salt level found in oceans. They also found that the water from this area collected in a lagoon nearby, on the shore of Lake Ontario, and it was poisoning the water. A geology professor from the university of Toronto named Nick Eyles stated that about 3,600 tons of road salt end up in the lagoon every winter and continue to poison it for the rest of the year. (more information about this incident can be found here)
Researchers at the University of Minnesota--Twin Cities conducted an experiment to discover the result of road salt after it is used on roads. They calculated the amount of salt being added to the system through road treatments, household use, wastewater dumping, agriculture, and other sources. They also calculated the amount of salt flowing out of salt flowing out of the system, though rivers and streams. They discovered that only about 30% of road salt used in the Twin Cities area is carried out by the Mississippi River, while the remaining 70% seeps into the area's watershed, posing as a contamination threat for residents in the area. Road salt seeps into rivers and lakes--more info
The issue of road salt having a negative effect on aquatic ecosystems was first recognized in the early 1960’s. Road salt usage in the United States increased consistently starting in the 1940’s up to this decade. Urban development has also increased rapidly, which causes a rise in the necessity of road salt to melt winter roads. 17 major metropolitan areas around the United States were sampled for chloride in the water quality. Samples were collected by submerging sample bottles in the center of a stream or by using a weighted-bottle sampler to collect cross-section samples from streams. At Wilson Park Creek in Milwaukee, some of the results of the toxicity of road salt were that in chronic C. Dubia, no young were produced when the chloride concentration was 1770 mg/L or greater. Complete mortality was seen as a result of chloride concentrations of 2420 mg/L or greater.More information on this experiment can be found here
(Road Salt Runoff Affects Ecosystems and their Inhabitants)
(Many Wildlife Species are Negatively Affected by Road Salt Runoff)
GOVERNMENTS (state, national) INTERACTIONS WITH ROAD SALTS:
- Citizens of the U.S.A. can use a lot of road salt every winter, ending up to be somewhere around 22 million tons of road salt are used, if not even more than that.
- Most common used road salt is sodium chloride, which is effective and inexpensive (NaCi)
- In the U.S eight to twelve million tons of NaCi road salt a year are used.
- Massachusetts alone alloted $35 million for snow removal instead of the previous years $15 million- if the state reduced salt use it would benifit them financially and environmentally
- Example of a government dealing with the problems (which mass. could follow their lead) that come from road salts: Canada setting up plans in advance for the use and amount of road salt
Alternatives:
-More high tech application of road salt will reduce amount used, however this is more costly- "The state of Indiana implemented this approach last winter, saving 228,000 tons of salt, and -More than $13 million dollars in salt and overtime costs, according to a state report."
-Alternatives to NaCi road salt include calcium magnesium acetate and potassium acetate- this site states that, "Even as road salt began to be implicated for environmental damage in the 1960s and 1970s, its use increased to 10 million tons annually in the U.S. and 3 million in Canada (SI 1983). By the 1990s, a variety of alternative deicers CMA, CG-90, NaFo, Freezgard + PCI, Ice Stop CI, Quiksalt + PCI, and urea—were shown to be effective in studies by the Washington Department of Transportation, the Federal Highway Administration, or the City of Ottawa, Ontario (Nevada Milepost 1993,Better Roads 1989, 1991)."
-By deicing the roads before the storm, less salt is needed
-"In addition to environmental benefits, using less salt slows its corrosive effects on bridges and cars."
-A Minnesota town is testing a previous pavement surface so that melting snow soaks right through, rather than running off into waterways.
-Place heating tubes under the roads to melt the ice without salt
-New plow blades prove to be more effective to eliminate layers of snow
-Wetting the road salt before placing it on the roads so the salt won't bounce off the road
- Properly store road salt on an impervious surface away from rain so that runoff doesn't cause damage in the environment or waste purchased road salt
- Deicers are usually utilized at a higher rate than recommended, so training applicators or programming road salt trucks by computer would be helpful to avoid overusing road salt, leaving extra behind after the snow is melted
- Wetting the road salt before use speeds the melting process and reduces the scatter of salt particles on the road when applied
Another site listing alternatives to road salts
**Here is a link of how you can help prevent road salt contamination
Some ways on how to prevent harmful effects of road salt are to not overuse salt on roads. Salt is only useful for thawing roads before snow and ice fall. By creating a layer of salty moisture that restricts freezing, it stops snow and ice to bond with pavement. More ways to prevent pollution is found here .
http://cseo.mtu.edu/community/publications/wellspring/.html summary of road salt and alternative strategies
Governments can limit the amount of road salt permitted to each state per road/highway
(salt storage)